Statistics Unit 5

• ≈10

• ≈15

• ≈55

• ≈75

• ≈25

• ≈470

• ≈3670

• ≈1850

A random sample of 100 visitors to a popular theme park spent an average of $142 on the trip with a standard deviation of $47.5. Which of the following would be the 98% confidence interval for the mean money spent by all visitors to this theme park?

• ($130.77, $153.23)

• ($132.57, $151.43)

• ($132.69, $151.31)

• ($140.88, $143.12)

• 0.75

• 0.16

• 3.6

• Cannot be determined without the actual data.

A sample of 40 people owned an average of 1.35 apple products. It is known from a previous study that the population standard deviation of apple product ownership is σ=0.63 products. Construct a 95% confidence interval for mean μ owned apple products.

• (1.11, 1.58)

• (1.15, 1.55)

• (1.19, 1.51)

• (1.09, 1.61)

Construct a 95% confidence interval for the population mean μ. Assume the population has a normal distribution. A sample of 25 randomly selected students has a mean test score of 81.5 with a standard deviation of 10.2

• (77.29, 85.71)

• (87.12, 98.32)

• (66.35, 69.89)

• (56.12, 78.34)

• 7.125 ± 1.19

• 7.125 ± 1.64

• 7.125 ± 1.28

• 7.125 ± 1.59

A sample of 30 women finds the mean height to be 62.3 in and the standard deviation to be 1.5 in. Find the margin of error of the mean woman's height for a 95% confidence interval.

• 1.699

• 0.56

• 0.537

• 1.12

In a crash test of 15 random troopers, collision repair costs are found to have a distribution that is approximately normal, with a mean of $1800 and a standard deviation of $950. Construct a 99% confidence interval for the mean of all repair costs.

• (1070, 2530)

• (1273, 2326)

• (1799, 1801)

• None of these.

A research group wishes to estimate the mean amount of time (in hours) that members of a fitness center spend exercising each week. They want to estimate the mean within a margin of error of 0.5 hours with a 95% level of confidence. Previous data suggests that the standard deviation σ = 2.2. Which of the following is the smallest sample size they could use?

• 60

• 75

• 90

• 180